Gimbal mechanisms

ABSTRACT

735,359. Self-levelling arrangements. ENGLISH ELECTRIC CO., Ltd. Jan. 1, 1954 [Jan. 9, 1953], No. 788/53. Class 113 (1). In a mechanism comprising a gimbal member 10 having two co-extensive part-circular opposed concentric surfaces and supported by two rollers 14, 15 both bearing upon one of the surfaces and at least one other roller 16 bearing upon that part of the other surface corresponding to the minor arc between said two rollers, means to move the gimbal member circumferentially between the rollers comprises a pair of rope-like members 17, 21 fastened at 18 and 22 respectively near each end of an outwardly facing surface of the gimbal member and passing around this surface over each of the rollers 14, 15 to a means for applying and controlling tension in the rope-like members. This latter means comprises a pair of fluid pressurecontrolled piston and cylinder units 25, 28 in which the rope-like members 17 and 21 respectively pass over pulleys 19, 23 mounted on a piston attachment 26 and have the ends which are not fastened to the surface of the gimbal member fastened to a fixed point 20, 24 in the mechanism. The gimbal member 10 supports, through pivotal bearings 11, 12, a reflector dish 13 for a radar aerial and is itself mounted on a frame (not shown) pivotally about an axis perpendicular to a plane containing the pivotal axis 11-12.

March 26, 1957 1. RUSSELL 2,786,361

GIMBAL MECHANISMS Filed Dec. 28, 1953 United States Patent GllVlBALMECHANISMS James Langley Russell, Luton, England, assignor to TheEnglish Electric Company Limited, London, England, a British CompanyApplication December 28, 1953, Serial No. 400,729 Claims priority,application Great Britain January 9, 1953 3 Claims. (Cl. 74-95) Thisinvention relates to a gimbal mechanism; i. e. a mechanism comprising agimbal member upon which a device is pivotally mounted, a gimbal memberitself being mounted on a frame pivotally about an axis perpendicular toa plane containing the pivotal axis of the device in the gimbal member.

According to a feature of the present invention, a mechanism comprises agimbal member having two coextensive part-circular opposed concentricsurfaces, means to support the gimbal member comprising two rollers bothbearing upon one of the surfaces and at least one other roller bearingupon that part of the other surface corresponding to the minor arcbetween said two rollers, and means to move the gimbal membercircumferentially between the rollers.

According to a further feature of the invention, said means to move thegimbal member comprises a pair of flexible rope-like members fastenedone near each end of an outwardly facing surface of the gimbal memberand passing around this surface over each of a pair of adjacentlydisposed pulleys to a means for applying and controlling tension in therope-like members. Said ropelike members may be lengths of cord,wire-rope, chain or tape, etc.

According to another feature of the invention, the means for applyingand controlling tension comprises a pair of fluid pressure-controlledpiston and cylinder units in which the rope-like members are eachfastened to a piston attachment.

According to a preferred feature of the invention the means for applyingand controlling tension comprises a pair of fluid pressure-controlledpiston and cylinder units in which the rope-like members each pass overa pulley mounted on a piston attachment and have the ends which are notfastened to the surface of the gimbal member fastened to a fixed pointin the mechanism.

According to a still further feature of the invention said pair ofadjacently disposed pulleys is formed by grooves in the two rollerswhich bear upon the surface of the gimbal member.

A gimbal mechanism which embodies the invention in preferred form isdiagrammatically illustrated in plan view in the accompanying drawing.

A semi-circular gimbal ring supports, through pivotal bearings 11 and12, the axis of which lies in the plane of the figure, a reflector dish13 for a radar aerial.

The gimbal member 10 is in turn supported from a frame (not shown) bypassing between two rollers 14 and 15 which are carried by the frame andbear upon the outside surface of gimbal member 10, and a further roller16 which bears on the inside surface and is also carried by the frame.

A flexible wire 17 is secured to gimbal member 10 at 18 and is wrappedaround the outside surface of gimbal member 10 to pass between thismember and roller 14. It then passes around a further roller 19 and hasits other end secured to the frame at a point 20.

A similar flexible wire 21 is secured to the other end of gimbal member10 at point 22 and passes between the gimbal member and roller 15,around roller 23 to an anchorage on the frame at point 24.

Roller 19 is secured to a piston 25 by a piston rod 26. Piston 25 worksin a hydraulic cylinder 27 to force roller 19 away and apply tension towire 17. Roller 23 is similarly forced by a corresponding piston 28 andhydraulic cylinder 29 to apply tension to wire 21.

By application of pressure fluid through the port 31 to cylinder 27 athigher pressure than fluid applied through the port 32 to cylinder 29,the tension in wire 17 may be increased above that in wire 21. Piston 25will then move outwards expelling fluid through the port 33 while piston28 moves inwards and fluid is admitted through the port 34 and gimbalmember 10 will be turned between rollers 14, 15 and 16 in the directionwhich appears anti-clockwise in the drawing. The ports 33 and 34 may beconnected together.

Rotation of reflector 13 about the axis of its bearings 11 and 12 isindependently effected by a motor diagrammatically indicated at 30.

It will be seen that the mechanism shown in the drawing can beconstructed to occupy a space of small overall width, which in someapplications is a great advantage.

What I claim as my invention and desire to secure by Letters Patent is:

1. A mechanism comprising a gimbal member having two co-extensivepart-circular opposed concentric surfaces, means to support the gimbalmember comprising two rollers both bearing upon one of the surfaces andat least one other roller bearing upon that part of the other surfacecorresponding to the minor are between said two rollers, and means tomove the gimbal member circumferentially between the rollers.

2. A mechanism according to claim 1, wherein said means to move thegimbal member comprises a pair of flexible rope-like members fastenedone near each end of an outwardly facing surface of the gimbal memberand passing around this surface over each of a pair of adjacentlydisposed pulleys to a means for applying and controlling tension in therope-like members.

3. A mechanism according to claim 2, wherein said pair of adjacentlydisposed pulleys is formed by grooves in the two rollers which bear uponthe surface of the gimbal member.

References Cited in the file of this patent UNITED STATES PATENTS

